Project Summary Functional drug fingerprinting with all-optical electrophysiology The Optopatch platform recently developed at Q-State Biosciences, which uses engineered optogenetic proteins, custom microscopes, and software, makes it possible to simultaneously stimulate (blue light) and record (red light) electrical activity from ~100 neurons with 1 millisecond temporal resolution, single-cell spatial resolution and high signal-to-noise ratio. The Optopatch assays can record hundreds of parameters characterizing intrinsic excitability and neuronal function in both rodent and human induced pluripotent stem cell-derived neurons. Using these tools, we propose to develop a ?drug fingerprint? database, where we characterize the impact of a library of drugs and tool compounds on neuronal excitability. The database will capture the unique functional effects of each compound and represent them as vectors in a reduced dimensionality fingerprinting space. The database can be leveraged in several ways in both internal programs and with pharma partners: 1) Identification of targets of hits from a phenotypic screen. ? Phenotypic screening offers the advantage of testing compounds in a disease-relevant cell type or animal model but has the disadvantage of not knowing the target(s) of effect. Target ID is essential information for de- risking the drug discovery process and matching the hits? functional effects to the drug fingerprint database can accelerate or augment standard target identification approaches. 2) Rapid identification of therapies in personalized medicine. ? Q-State is expanding capabilities to identify therapeutic approaches for patients with severe genetic disorders who have a short life expectancy. Optopatch has identified functional deficits in neurons derived from individual patients relative to healthy controls, and we hope the drug fingerprint database can be used to expedite and focus therapy selection to those with high potential to correct the problem. This obviates the need to screen and entire drug library in patient neurons; requiring only the most promising compounds to be tested and saving time for a patient where time is limited. In this proposal, we first assemble the library and build the drug fingerprint database. We then test the two applications. Fidelity of target identification is tested using compounds with known targets, and the ability to identify phenotype-reversing drugs is tested using cell lines and phenotypes already established at Q-State. The tools developed will be a permanent asset and should catalyze the development of new therapeutics.